CNT-Polymer Composite Applications

Nanometer-size catalyst supports have recently attracted great attention because of their high surface area and outstanding stabflity and activity in the liquid phase. In particular, CNT-supported catalysts have been selected for highly efficient catalysis because they provide different contact areas that can be functionalized in various ways. Several routes have been developed to link the catalytic metal nanopartides to the CNT surface 89]. Examples include chemical deposition with and without the aid of redudng agents, electrochemical deposition, and direct assembly of metal nanopartides onto pristine and/or modified CNT sidewalls. 

Alternatively, CNT-polymer composites have been utilized as polymer electrolyte membranes in fuel cell devices (PEMFCs) [111]. Sulfonic acid-functionalized CNTs were blended with Nafion polymer so that the proton transport capability of the polymer matrix could be enhanced appreciably. Ionic conductivity measurements of Nafion and CNT-Nafion membranes revealed almost one order of magnitude higher conductivity for the composite than that for neat matrix. 

29 Velasco-Santos, C., Martinez-Hemandez, A.L, Fisher, F.T., Ruoff R., and Castano, V.M. (2003) Chemistry of Materials, 15, 4470. 

40 Spitalsky, Z., Tsoukleri, G., Tasis, D., Krontiras, C., Georga, S., and Galiotis, 

58 Vigolo, B., Poulin, P., Lucas, M., Launois, P., and Bernier, P. (2002) Applied Physics Letters, 81, 1210. 

---

Joo and co-workers [22] have discussed a new type of composite membrane, consisting of functionalised carbon nanotubes (CNT) and sulfonated polyarylene sulfone (sPAS) for direct methanol fuel cell applications. The CNT modified with sulfonic acid or platinum-rubidium (PtRu) nanoparticles were dispersed within the sPAS matrix by a solution casting method to give SOs-CNT-sPAS or PtRu-CNT-sPAS composite membranes, respectively. Characterisation of the composite membranes revealed that the functionalised CNT were homogeneously distributed within the sPAS matrix and the composite membranes contained smaller ion clusters than the neat sPAS. The composite membranes exhibited enhanced mechanical properties in terms of tensile strength, strain and toughness, which leads to improvements in ion conductivity and methanol permeability compared with the neat sPAS membrane, which demonstrates that the improved properties of the composite membranes induce an increase in power density. The strategy for CNT-sulfonated composite membranes in this work can potentially be extended to other CNT-polymer composite systems. 

It must be noted that CNTs are promising material for preparing various composites, which can also be used for gas sensor design. Types of composites formed using CNTs according to their chemical composition and structures are summarized in Fig. 1.14. Features of CNT/polymer composites, which have the most evident advantages for gas sensor application, will be discussed in Chap. 13 (Vol. 2). It was established that polymer/CNT composites combine the unique properties of nanotubes with the ease of processability of polymers. Moreover, for design multifunctional materials based on CNT/polymer composites, a very low fraction content of CNT is required. 

A particular kind of CNTs-polymer composites is represented by CNTs-MIPs composites, in which the polymer part is a molecularly imprinted polymer (Chang et al., 2011 Walcarius et al, 2005). CNTs impart electrical conductivity to MIPs, while molecular imprinting on these one-dimensional nanostructures will endow the nanotubes with molecular recognition functions, further expanding their application fields (Guan et al., 2008). Several example of using these materials are reported in literature for biomedical, pharmaceutical and environmental applications (Figure 6). 

The current review summarizes the recent progress made in electrospun CNT-polymer composite nanofiber, along with their processing, characterization, mechanical properties, and applications. Theoretical investigations on mechanical properties of CNT and CNT-based polymer composite are also addressed. Finally, research challenges and future trends in modeling and simulation of electrospun polymer composite nanofibers are discussed. 

Food for Thought Possible Applications of CNT/Polymer Composites ... 

In this chapter, the development of functional CNT-polymer composites in recent years will be addressed in detail. The focus will be on processing methods for fabricating the superstrong and/or conductive composite materials. In addition, important aspects of the mechanical and electrical behavior of CNT-polymer composites as well as their potential applications will be analyzed. 

Finally, SWCNT concentrations higher than 0.3 and 3wt%, respectively are sufficient for applications in electrostatic painting and electromagnetic interference shielding, respectively (Figure 10.8). Other applications of electrically conductive CNT-polymer composites are in printable circuit wiring and as transparent conductive coatings. 

---